package com.springcloud.zuul.common.utlis;

import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import lombok.extern.slf4j.Slf4j;

/**
 * @program: springcloud-zuul
 * @description:
 * @author: zhlu
 * @create: 2019-12-30 12:14
 * @Introduction(说明背景故事)
 **/
@Slf4j
public class listToTreeUtils {

    private  listToTreeUtils(){
        log.info("");
    }

    /**
     * Description:list转tree树形
     * @author zhlu
     * @date 2019/12/30 12:14 下午
     * @param arr
     * @param id
     * @param pid
     * @param child
     * @return com.alibaba.fastjson.JSONArray
     */
    public static JSONArray buidTree(JSONArray arr, String id, String pid, String child) {
        JSONArray r = new JSONArray();
        JSONObject hash = new JSONObject();
        //将数组转为Object的形式，key为数组中的id
        for (int i = 0; i < arr.size(); i++) {
            JSONObject json = (JSONObject) arr.get(i);
            hash.put(json.getString(id), json);
        }
        //遍历结果集
        for (int j = 0; j < arr.size(); j++) {
            //单条记录
            JSONObject aVal = (JSONObject) arr.get(j);
            //在hash中取出key为单条记录中pid的值
            String pidStr = "";
            Object pidObj = aVal.get(pid);
            if (aVal.get(pid) != null) {
                pidStr = aVal.get(pid).toString();
            }
            JSONObject hashVP = (JSONObject) hash.get(pidStr);
            //如果记录的pid存在，则说明它有父节点，将她添加到孩子节点的集合中
            if (hashVP != null) {
                //检查是否有child属性
                if (hashVP.get(child) != null) {
                    JSONArray ch = (JSONArray) hashVP.get(child);
                    ch.add(aVal);
                    hashVP.put(child, ch);
                } else {
                    JSONArray ch = new JSONArray();
                    ch.add(aVal);
                    hashVP.put(child, ch);
                }
            } else {
                r.add(aVal);
            }
        }
        return r;
    }
}
